Search

Transitioning electricity generation sectors to renewable energy is a necessary element of climate change mitigation but a challenging one with years of technical and social lock-in creating considerable inertia and a pace of change insufficient to meet the task. Transition management has emerged as a promising approach to proactively manage and accelerate transitions in sectors like energy and water and has the potential to do so in manner that would help secure energy justice. However, the approach has been criticised for ignoring the political dynamics of transitions, risking procedural and recognition injustice for traditional energy production regions while increasing opposition to a transition. This paper uses a qualitative case study approach to understand how a transition to renewable energy generation could be achieved in a way that secures energy justice for traditional energy production regions like those of Gladstone in the Australian state of Queensland. The paper augments the transition management approach with the “just transitions” concept, which has emerged from labour movements as a means to mitigate negative impacts on workers and communities in traditional energy production regions, to create a “Just Transition Management” framework that is applied as a diagnostic tool to the case study. While results suggest a transition is imminent within Queensland, a lack of: consistent, supportive federal policy; long-term visions, and a clear process leaves it at risk of being captured by the powerful incumbent resources sector utilising an “environment vs. jobs” narrative. Yet, the results also suggest that adopting a just transition management approach has the potential to successfully resist the influence of the resources sector, by providing cheap, secure renewable energy and supporting affected workers into roles in the renewable energy sector using a reflexive, representative network governance approach. Data analysis reveals how the application of just transition principles has already engaged communities and unions that were previously sceptical of renewable energy. Overall, this study suggests that the just transition management framework assists in identifying the political barriers to transitions and energy justice more broadly, while also providing a management approach which creates powerful niche actor-networks to counter the narratives and influence of the incumbent resource sector. Thus it could support successful transitions that achieve the distributional, recognition and procedural justice needed for energy justice globally. [ABSTRACT FROM AUTHOR]

This paper presents a model for estimating the amount of distributed generation solar photovoltaics (DGPV) that can be accommodated by an electrical system, limited by the ability of existing generation infrastructure to change output. The model is applied to a region of seven states in the U.S. Midwest, showing the potential for temporary curtailment of installed DGPV to mitigate those constraints, and the associated reductions in coal- and natural gas-fired electricity generation. Scenarios considered are those under which 100%, 99.5%, and 95% of available solar can be utilized, and the point at which DGPV curtailment can no longer mitigate constraints because of the inability of conventional generation to keep pace as solar output declines in the late afternoon. The model is developed using historical hourly fuel use data for electricity generation, hourly solar capacity factor, and carbon emissions factors. The model includes a generalized linear model, constructed by regression analysis, used to allocate potential reductions in conventional generation in response to demand changes caused by DGPV. Limits on output and ramping of conventional generation are considered and initially mitigated, where possible, by changes in hydroelectric generation. Results indicate that a substantial amount of DGPV can be accommodated without any changes to current generation infrastructure, and that small amounts of curtailment enable greater DGPV capacity and generation. In a scenario without curtailment, DGPV could provide about 6% of total generation in the modeled region. With just 0.5% curtailment at DGPV installations, roughly 9% of generation could be provided by DGPV. Ultimately, up to 14% of generation could be achieved through DGPV installation before technological limitations would diminish the ability to meet all demand with further increased DGPV. [ABSTRACT FROM AUTHOR]

Electric energy generation from renewable energy sources is generally non-dispatchable due to its intrinsic volatility. Therefore, its integration into electricity markets and in power system operation is often based on volatility-compensating energy storage systems. Scheduling and control of this kind of coupled systems is usually based on hierarchical control and optimization. On the upper level, one solves an optimization problem to compute a dispatch schedule and a coherent allocation of energy reserves. On the lower level, one performs online adjustments of the dispatch schedule using, for example, model predictive control. In the present paper, we propose a formulation of the upper level optimization based on data-driven probabilistic forecasts of the power and energy output of the uncontrollable loads and generators dependent on renewable energy sources. Specifically, relying on probabilistic forecasts of both power and energy profiles of the uncertain demand/generation, we propose a novel framework to ensure the online feasibility of the dispatch schedule with a given security level. The efficacy of the proposed scheme is illustrated by simulations based on real household production and consumption data. [ABSTRACT FROM AUTHOR]

Chongming’s current energy system is highly import-dependent and the distributed energy system with high renewable energy penetration should be taken into consideration. In this paper, a simulation model based on EnergyPLAN software with 2014 as the reference year is developed to represent Chongming’s present energy structure. Four future scenarios which propose different further energy constructions have been observed. Results show that reductions in primary energy consumption, electricity import, annual operating costs as well as CO 2 emissions are realizable when switching to an energy system with a high share of renewable sources combining natural gas CHP (Combined Heating and Power). After preliminary discussions, the feasibility of different renewable sources penetration are analyzed through calculating the excess electricity production (CEEP). The estimated optimal combination is generated when the PV fraction is 20% while wind energy fraction is 80%. Moreover, the analyses have taken into account that several flexible techniques are needed in order to balance supply and demand and to ensure the grid voltage and frequency stabilities. As a result, through the recommended three techniques, the excess production can be avoided as far as a renewable energy input of up to nearly 60%. [ABSTRACT FROM AUTHOR]

Energy storage is more important today than ever. It has a key role in storing intermittent electricity from renewable sources – wind, solar and waves – enabling the decarbonisation of the electricity sector. Liquid air energy storage (LAES) is a novel technology for grid scale energy storage in the form of liquid air with the potential to overcome the drawbacks of pumped-hydro and compressed air storage. In this paper we address the performance of next generation LAES standalone plants. Starting our experience with LAES pilot plant at Birmingham (UK), we developed for the first time a validated model to address the dynamic performance of LAES. The model allows us to understand the relationship between component and system level performance through dynamic modelling. We found that the temporary storage of cold thermal energy streams using packed beds improves efficiency of LAES by ∼50%. However, due to dynamic cycling charge/discharge, packed beds can bring an undesired 25% increase in the energy expenditure needed to liquefy air. In summary, this work points outs that (a) dynamics of LAES should not be neglected; (b) novel design for cold thermal storage are needed and (c) linking component and system level performance is crucial for energy storage. [ABSTRACT FROM AUTHOR]

In this paper we study the performance of 855 large (⩾10 kW) commercial rooftop photovoltaic (PV) system installations in California. Drawing on the nonparametric data envelopment analysis (DEA) method, our study takes the PV capacity, electricity generation, modules, system cost, solar irradiance, and ambient air temperature into account to provide a unified measure of the PV installation performance. This approach can overcome some of the limitations of simple output-to-input ratio analysis and allow us to assess whether solar capacity and electricity generation have been efficiently integrated into the grid in a holistic way. We find widespread inefficiencies in roughly 80–90% of the installations both within a specific year and across different years. There is a significant efficiency gain in solar installation from 2008 to 2012. Through regional analysis, we find high dispersions of performance across counties and cities, and identify locations where PV installations have achieved the best performance. The analysis also sheds lights on the magnitude of the gap between inefficient installations and efficient ones. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a power production system for the isolated insular power system of the islands Karpathos and Kasos. Karpathos and Kasos are two small islands, located in the South-East Aegean Sea (Dodecanese complex) that are not connected to the main power distribution network. Energy production is based exclusively on an autonomous thermal power plant and a small wind park, installed on the island of Karpathos. The maximum annual power demand has been estimated to exceed 12MW by 2014. The mean specific annual energy production cost from the existing system has been calculated at 0.249€/kWh in 2008. The proposed system aims at the maximisation of wind energy penetration and the minimisation of imported fossil fuel use for the production of electricity. The proposed system consists of a wind park and a pumped storage system (PSS). The introduced power system aims to guarantee power production for certain hours per day. A thorough sitting of the system is accomplished. Three different sites for the PSS installation are examined before the optimum is selected. The available wind potential of the islands was evaluated using a wind mast installed within the frame of the examined project’s feasibility study. The annual mean wind velocity at the wind park’s installation site was measured to be higher than 11.5m/s. The introduced system’s set-up, and operation & maintenance cost parameters have been estimated. The dimensioning of the system aims mainly at optimising the project’s economic indexes, following the existing legislative framework. The annual guaranteed energy production has also been maximised. An economic sensitivity analysis is performed. It is estimated that the proposed project can exhibit attractive economic indexes, regardless of the availability of a subsidy, on the condition that the selling price of energy should be configured at 0.3552€/kWh and the selling price of guaranteed power should be 127€/kWyear. Under the above mentioned prerequisites, the project payback period is estimated at 5–6years. The present paper proves the economic feasibility of small scale wind powered pumped storage systems, not taking into account the undoubted environmental benefits. [Copyright &y& Elsevier]

Stabilization at concentrations consistent with keeping global warming below 2 °C above the pre-industrial level will require drastic cuts in Greenhouse Gas (GHG) emissions during the first half of the century; net negative emissions approaching 2100 are required in the vast majority of current emission scenarios. For negative emissions, the focus has been on bioenergy with carbon capture and storage (BECCS), where carbon-neutral bioenergy would be combined with additional carbon capture thus yielding emissions lower than zero. Different BECCS technologies are considered around the world and one option that deserves special attention applies CCS to ethanol production. It is currently possible to eliminate 27.7 million tonnes (Mt) of CO 2 emissions per year through capture and storage of CO 2 released during fermentation, which is part of sugar cane-based ethanol production in Brazil. Thus, BECCS could reduce the country’s emissions from energy production by roughly 5%. Such emissions are additional to those due to the substitution of biomass-based electricity for fossil-fueled power plants. This paper assesses the potential and cost effectiveness of negative emissions in the joint production system of ethanol and electricity based on sugar cane, bagasse, and other residues in Brazil. An important benefit is that CO 2 can be captured twice along the proposed BECCS supply chain (once during fermentation and once during electricity generation). This study only considers BECCS from fermentation because capturing such CO 2 is straightforward, thus potentially representing a cost-effective mitigation option for Brazil compared to other alternatives. The assessment shows that fuel prices would increase by less than 3.5% due to the adoption of BECCS from fermentation, while increasing investors’ revenues are sufficient to compensate for the investment required. With appropriate government subsidies, or by sharing BECCS costs between all car fuels and all electricity supplied by hydro and bioelectricity, the increment in ethanol and electricity prices could be less than 1% for the final consumer. Meanwhile it would supply 77.3% of all cars’ fuel (private cars) and 17.9% of all electricity in Brazil. [ABSTRACT FROM AUTHOR]

Abstract: Portugal is a country with an energy system highly dependent on oil and gas imports. Imports of oil and gas accounted for 85% of the country’s requirements in 2005 and 86% in 2006. Meanwhile, the share of renewable energy sources (RES) in the total primary energy consumption was only 14% in 2006. When focusing only on electricity production, the situation is somewhat better. The share of RES in gross electricity production varies between 20% and 35% and is dependent on the hydropower production in wet and dry years. This paper presents, on a national scale, Portugal’s energy system planning and technical solutions for achieving 100% RES electricity production. Planning was based on hourly energy balance and use of H2RES software. The H2RES model provides the ability to integrate various types of storages into energy systems in order to increase penetration of the intermittent renewable energy sources or to achieve a 100% renewable island, region or country. The paper also represents a stepping-stone for studies offering wider possibilities in matching and satisfying electricity supply in Portugal with potential renewable energy sources. Special attention has been given to intermittent sources such as wind, solar and ocean waves that can be coupled to appropriate energy storage systems charged with surplus amounts of produced electricity. The storage systems also decrease installed power requirements for generating units. Consequently, these storages will assist in avoiding unnecessary rejection of renewable potential and reaching a sufficient security of energy supply. [ABSTRACT FROM AUTHOR]

In this paper we study development patterns of Latvian electricity market. It is done based on a newly developed computer-aided simulation model. System dynamics approach was used to simulate long-term development of electricity sector in the region under the existing policy design. Results demonstrate that renewable energy sources have a high potential to integrate in the electricity generation balance. Important preconditions for this to happen are: presence of appropriate support measures, a continuous technological progress and fossil fuel price increase. Under such scenario around 70% carbon dioxide emission savings can be achieved by 2050. [ABSTRACT FROM AUTHOR]

The activation of demand response (DR) potentials offered by electricity consumer flexibility is one promising option for providing balancing power and energy in supply systems with high share of variable renewable energy (VRE) power generation. In this paper, a model-based assessment of the economic DR potential in Germany is presented. It relies on the extension of the REMix energy system model by flexible electric loads. In a case study considering a future German power supply system with a VRE share of 70%, possible cost reductions achieved by investment in DR are quantified. The sensitivity of the results to changes in the assumed DR costs and characteristics are analyzed in additional simulations. The results show that the major benefit of employing DR is its ability to substitute peak power generation capacity, whereas the impact on the integration of VRE power generation is lower. This implies that the focus of DR is on the provision of power, not energy. Even at rather pessimistic cost DR assumptions, more than 5 GW of power plant capacity can be substituted. Consumer flexibility furthermore triggers an increase in the operation of back-up power plants, whereas it decreases the utilization of pumped storage hydro stations. In the model results, the reductions in annual power supply costs achieved by DR add up to several hundreds of millions of Euros. [ABSTRACT FROM AUTHOR]

Abstract: If considering the increased utilisation of renewable electricity during the last decade, it is realistic to assume that a significant part of future power production will originate from renewable sources. These are normally intermittent and would cause a fluctuating electricity production. A common suggestion for stabilising intermittent power in the grid is to produce hydrogen through water electrolysis thus storing the energy for later. It could work as an excellent load management tool to control the intermittency, due to its flexibility. In turn, hydrogen could be used as a fuel in transport if compressed or liquefied. However, since hydrogen is highly energy demanding to compress, and moreover, has relatively low energy content per volume it would be more beneficial to store the hydrogen chemically attached to carbon forming synthetic methane (i.e. biogas). This paper presents how biogas production from a given amount of biomass could be increased by addition of renewable electricity. Commonly biogas is produced through digestion of organic material. Recently also biomass gasification is gaining more attention and is under development. However, in both cases, a significant amount of carbon dioxide is produced as by-product which is subject for separation and disposal. To increase the biogas yield, the separated carbon dioxide (which is considered as climate neutral) could, instead of being seen as waste, be used as a component to produce additional methane through the well-known Sabatier reaction. In such process the carbon could act as hydrogen carrier of hydrogen originating from water electrolysis driven by renewable sources. In this study a base case scenario, describing biogas plants of typical sizes and efficiencies, is presented for both digestion and gasification. It is assessed that, if implementing the Sabatier process on gasification, the methane production would be increased by about 110%. For the digestion, the increase, including process improvements, would be about 74%. Hence, this method results in greatly increased biogas potential without the addition of new raw material to the process. Additionally, such model would present a great way to meet the transport sector’s increasing demand for renewable fuels, while simultaneously reducing net emissions of carbon dioxide. [Copyright &y& Elsevier]

Abstract: The technical and economic feasibility study of an innovative wind–solar hybrid renewable energy generation system with rainwater collection feature for electrical energy generation is presented in this paper. The power generated would supply part of the energy requirements of the high-rise building where the system is installed. The system integrates and optimizes several green technologies; including urban wind turbine, solar cell module and rain water collector. The design was conceptualized based on the experiences acquired during the development and testing of a suitable wind turbine for Malaysian applications. It is compact and can be built on top of high-rise buildings in order to provide on-site renewable power to the building. It overcomes the inferior aspect on the low wind speed by channeling and increasing the speed of the high altitude free-stream wind through the power-augmentation-guide-vane (PAGV) before it enters the wind turbine at the center portion. The shape or appearance of the PAGV that surrounds the wind turbine can be blended into the building architecture without negative visual impact (becomes part of the building). The design improves the starting behavior of wind turbines. It is also safer to people around and reduces noise pollution. The techno-economic analysis is carried out by applying the life cycle cost (LCC) method. The LCC method takes into consideration the complete range of costs and makes cash flows time-equivalent. The evaluations show that for a system with the PAGV (30m diameter and 14m high) and an H-rotor vertical axis wind turbine (17m diameter and 9m high) mounted on the top of a 220m high building, the estimated annual energy savings is 195.2MWh/year. [Copyright &y& Elsevier]

Abstract: In order to promote the production and use of electricity generated from renewable energy sources, support schemes such as the Renewables Portfolio Standard and various green power programs have been implemented. When evaluating the costs and benefits associated with those schemes, people need accurate information about the characteristics of renewable generation. The objective of the present paper is to identify the kind of information to be provided to lay people in Japan in order to enhance their understanding of biomass generation. We used the two-stage “mental model” method to conduct open-ended interviews and a questionnaire survey to reveal people’s beliefs about biomass generation. From the survey results, it was identified that the information to be provided should include the following: (a) definitions of biomass and biomass generation, (b) specific generation technologies, (c) the carbon neutral concept of biomass, (d) non-use of energy food crops in Japan, (e) sustainable availability of resources under certain conditions, and (f) high generation costs with their causes, such as collection costs of resources. [Copyright &y& Elsevier]

The entry of Poland into the European Union will require significant adjustment processes in the energy sector. This paper gives an overview of the current electricity-industry restructuring approaches employed in the European Union and Poland, with a focus on the promotion of the use of renewable-energy sources for electricity generation, and it assesses the policy implications of the accession of Poland into the European Union. [Copyright &y& Elsevier]

[Display omitted] • Tighter EU ETS target (−63% instead of −43% in 2030) speeds up transformation by 3–17 years. • Renewable share >74% in 2030, EU-wide coal phase-out almost completed by 2030. • Tighter target decreases cumulative emissions by 54%, increases costs by only 5%. • Carbon prices increase to 129EUR/tCO 2 in 2030 under ambitious ETS target. • Unavailability of fossil CCS and/or nuclear does not affect results. The EU Green Deal calls for climate neutrality by 2050 and emission reductions of 50–55% in 2030 in comparison to 1990. Achieving these reductions requires a substantial tightening of the regulations of the EU emissions trading system (EU ETS). This paper explores how the power sector would have to change in reaction to a tighter EU ETS target, and analyses the technological and economic implications. To cover the major ETS sectors, we combine a detailed power sector model with a marginal-abatement cost curve representation of industry emission abatement. We find that tightening the target would speed up the transformation by 3–17 years for different parts of the electricity system, with renewables contributing 74% of the electricity in 2030, EU-wide coal use almost completely phased-out by 2030 instead of 2045, and zero electricity generation emissions reached by 2040. Carbon prices within the EU ETS would more than triple to 129€/tCO 2 in 2030, reducing cumulated power sector emissions from 2017 to 2057 by 54% compared to a scenario with the current target. This transformation would come at limited costs: total discounted power system costs would only increase by 5%. We test our findings against a number of sensitivities: an increased electricity demand, which might arise from sector coupling, increases deployment of wind and solar and prolongs gas usage. Not allowing transmission expansion beyond 2020 levels shifts investments from wind to PV, hydrogen and batteries, and increases total system costs by 3%. Finally, the unavailability of fossil carbon capture and storage (CCS) or further nuclear investments does not impact results. Unavailability of bioenergy-based CCS (BECCS) has a visible impact (18% increase) on cumulated power sector emissions, thus shifting more of the mitigation burden to the industry sector, but does not increase electricity prices or total system costs (<1% increase). [ABSTRACT FROM AUTHOR]